Here is my problem. Picked up the '88 Regal SE 33' in California mid-January. On way back to Tennessee noticed some transmission slip and transmission oil temp getting quite high on long uphill grades.

I had the transmission rebuilt, yet the transmission oil temp still gets quite high.

The coach currently has a transmission oil cooler. I am thinking of adding a new cooler with a fan I can control (via switch) inside the coach. I am also going to add Bill H's mod to the engine area to direct more air through the coolers.

Note that the engine temp does not get hot, even though the trans temp does.

Is there anything else I should be looking at? Any and all ideas/suggestions would be appreciated.

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How about yhe gage?


Charles

I should have mentioned that the Barth is on the P30 chassis/GM drive train.

I ordered and received a new sensor and guage which I will be installing to verify temps.

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In the FWIW and BoyToy departments, I have a RAYTEK MiniTemp I have found very useful for such problems. It was purchased at Grainger for about $100. I have used it for checking temps in the engine compartment, cooling temps from the A/C vents, tire temps (tread and sidewall), water temps in the harbor etc.
I think it is one of the better toys I have, ranking up with a GPS.
This should help you to find both ext. temp on the tranny, temps on the lines and cooler. It could be blocked line etc.
Tim

hi ppp take out dash a.c. and condenser put oil cooler in front of rad. when engine fan comes on for heat. trans needs cooling to.you do not need fans.carl

Does the coach already have a trans cooler installed in front of the radiator?

If it does, it is too small. If it does not, you need one. I like these:

http://www.bulkpart.com/cgi-bin/miva?Merchant2/merchant...&Category_Code=TCCHD

Bigger is better. The 4589 is not enough for my 502. I am going to buy a 4739.

Getting rid of the dash air and its condenser is good. Search this site.

As for fans, a fan can indeed help your trans cooler, oil cooler or radiator if you are in a low air flow situation, like gridlock or horsing your way in to a difficult boondock site. I have a large puller fan behind my radiator, and I can see the trans temp go down when I switch it on in the above described situations. My previous P30 had two fans blowing on the trans cooler, and they also made a difference. Go ahead and don't use a fan and see what happens. If you don't get in to bad situations, you might not need one. If you do, you can add one later. You should not need an electric fan on the road.

Since your engine did not get hot, your transmission problem is probably not a fan problem, but it would be good to find out now how good it is instead of this summer on a hill on sunday afternoon on the way home. The factory fan clutch is very good, but only lasts a few years. Did your fan roar when things got hot? Test it by warming up the engine, then covering the radiator with newspaper. The fan should start to ROAR at 205 to 210 degrees.

Bill H.,

Yes, the coach already has a trans cooler installed in front of the radiator.

I have searched the site regarding the dash air and condenser and am considering it, although I am concerned re: defrosting in cooler weather - do you think this will be a problem?

The factory radiator fan does roar when the engine temp gets over 200 degrees, but the trans oil temp guage will read 260+ on grades with the engine temp guage reading <200.

When you had the trans rebuilt, did they replace the converter?

As far as removing the dash air, I can't give an answer on the defroster. I know in an automobile, cooled air is mixed with heated air for the defroster, to dry the air. In a P30, I don't really know about the cooled air part. But you will still have the heated air for the defroster. In the Southwest, defrosters do not have to work too hard.

You could raise the doghouse and operate the defroster and observe the compressor clutch to find the answer.

Yes, when they rebuilt the trans, the converter was replaced.

I will play with the defroster and compressor clutch to allay my fears fo removing.

I don't think removing the dash air will be of much help with your trans temp problem. I did it on mine for general cooling and economy reasons, but I don't think it will help enough to get your trans temps down where they should be.

Is the heat exchanger in the left radiator tank still in the circuit?

Yes, the rad heat exchanger is still in the oil cooler circuit.

I just referred to my ancient, dog-eared Trailer life RV Performance & Mileage manual. John Geraghty, erstwhile T.L. performance guru, advised that overfilling the tranny can cause the gears to run in the oil, aerating the oil, which then cannot be cooled properly.

You might double-check your oil level. It should be slightly below the "add" mark cold, about halfway up to "full" at normal operating temperature, and at the "full" mark only when really hot, like after a long climb.

Be sure to run it through the gears before you check it, and check it in "neutral." The oil doesn't pump when it's in "park."

Geraghty also says ideal oil temps are between 180 & 220 degrees F., but I know you're going to see higher temps climbing, towing, or bucking a headwind.

FWIW, on my previous s.o.b., my local tranny shop, which I respect, couldn't figure out how to mount a trans. cooler. I went to J.C. Whitney, bought a fan-cooled cooler, and a 180 degree in-line thermostat, mounted the cooler remotely, and it worked like gangbusters. Not cheap, at more than $200.00 total, but cheaper than replacing a tranny.

The machinery is so close to the front of the Barth, there might not be room for this cooler in front of the rad., if the a.c condenser is still there, but it's worth a thought and a measurement .

That's a thermostatically controlled fan switch, not just a thermostat.

Olroy is right--anything John Geraghty says is Gospel. He ran a dyno shop and was really good for boats and tow vehicles, unlike other L.A. dyno shops. He helped me improve everything from a slant six (in a Cortez) to my rump-rump boats. I wish he was still around.

My Barth has plenty of room in front of the radiator. I guess now your choice is rather like mine........

1.Replace the present cooler with a bigger one,

2.Use an additional remote cooler with a fan,

3.Combine both, using the present one as a remote with a fan.

I will probably do the combination. If you do not have an overheat problem at slow speeds, an air scoop and a duct could supply enough air for a remote cooler.

PAW or Southern Rods are good suppliers for fans. Southern Rods has some good prices, but I should warn that their service can be spotty.

I would further opine, thus: If 'twere mine, and the oil level was correct, and I ran in the 180 - 220 range in level flight, I'd not worry about short stints up hills, at higher temperatures. It is sustained overheating that breaks down the oil, and destroys transmissions.

Just check your oil often enough to disclose any discoloration, or change in odor. Change it at the first hint of breakdown, and keep your filters clean. Motorhome and tow vehicle trannys have to work a lot harder than the one in your car.